My 89-300ce had a high idle, 1500-1700rpm in neutral, hot or cold. Sometimes it would drop down to normal idle, sometimes not.

- Removed the OVP and idle was steady at 800RPM so its not the OVP.

- From reading this forum idle that high = air but 800rpm idle with OVP removed suggests no vacuum leaks, computer must be opening ICV valve for some reason.

- Checked the ICV anyway, clean, cleaned it with carb cleaner just because.

- Reading previous posts from Duke2.6 made me check the throttle valve switch. Idle switch never closed. Bingo!

- Letting the throttle slam closed gave me temp reading of 800 ohm then open again. Linkage worked fine.

- Duke2.6 said he sprayed with carb cleaner and fixed it but that didn't make sense since the switch is totaly enclosed. Sprayed the switch, linkage, etc. with carb cleaner anyway. Ohms started to drop. Huh?

- Continued to spray linkage etc. with carb cleaner and worked the throttle valve until resistance stayed steady at 0.8ohms closed everytime. I suspect that the link rod down to the cruise thingy was gummed up.

- Reconnected everything and car idles steady at approx. 600rpm

- Thanks Duke2.6 and Forum !!

Yes, I was surprised, too, but it looked like removing that switch would be a bear because of the lack of access to the mounting screws, so I just tried cleaning the area with carb cleaner and it worked!

The other thing I did was remove the lower linkage to clean and lubricate (with white lithium grease) all the links with ball joints.

Duke

I've seen problems using Li Grease in those fittings...

I'd stick to the factory recommendation of ATF. I think linkage cleaning and Lub is part of the 30k service(?).


Michael

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Michael McGuire
83 300d
01 vw A4 TDI
66 Chevy Corsa
68 GMC V6 w/oD
86 300E

Does the m104 engine have this throttle valve switch? If so, where can it be found.

Thanks,
Matt
94 e320

Does soemone have a picture of the throttle valve switch? What does it look like?

The throttle valve housing is bolted directly onto the top of your intake manifold, it is below your air flow meter which is below your air cleaner.


The throttle valve switch is approx 1"x1"x1/8" and is mounted on the outside of the throttle valve housing (it faces the front of your car) on the opposite side of where the throttle valve is actuated by your throttle lever. It has a wire loom that runs up to a three prong connector mounted for easy access on your intake manifold near the ICV.

I'm not sure if the m104 has a TVS.

Thanks. I have an M102 and I have been looking for a sticky throttle cable or broken return spring and haven't been able to find anything wrong.